The present invention relates to a semiconductor device having a wiring layer composed of a silicon film and an aluminum film with an improved contact structure thereof.
A wiring layer made of pure aluminum or silicon-aluminum alloy is apt to break by moisture on an insulating layer. To avoid this disadvantage, a wiring layer composed of a doped polycrystalline silicon film attached to the insulating layer and an aluminum film provided on the silicon film and having the same shape with the under silicon film has been proposed. However, the prior art structure has a high contact resistance because in the contact hole the doped polycrystalline silicon film is interposed entirely between the aluminum film and an impurity region of the monocrystalline silicon substrate.